The contract would have expired Sunday at midnight had the two not worked out differences that had caused Memorial Hermann to alert patients and Blue Cross to alert enrollees that the relationship was in danger.

The squabble, which has lasted since 2012, involved a new and more expensive payment and care delivery model, known as an accountable care organization, that Memorial Hermann is adopting ahead of federal health-care reform. The law incentivizes such models.

Blue Cross is Texas' largest health insurer, with 5 million members in the state and 1 million in the Houston area. Memorial Hermann is Houston's largest health care provider, with 11 hospitals, numerous specialty programs and clinics throughout the area.